1. Field of the Invention
The present invention relates to a liquid ejection apparatus (mechanism) and an image forming apparatus, and more particularly to a liquid ejection apparatus including an ink supply system and a serial head connected with a sub tank for supplying ink, the sub tank being connected to a main tank for supplying the ink.
2. Description of the Related Art
In recent years, due to requirements for higher image quality, particular emphasis has been given to research into stabilizing the ejection volume of liquid droplets and improving the accuracy of the depositing positions. Japanese Patent Application Publication No. 2004-42395 discloses technology of stabilizing the flight direction of the ink droplets. FIGS. 11A to 11E are diagrams showing the progress of the ejection of ink from a nozzle according to Japanese Patent Application Publication No. 2004-42395. As shown in FIGS. 11A to 11E, a second bubble generation chamber 26B which abuts against a nozzle plate 40 (orifice substrate), is provided. Thereby, the ink that is to be ejected through expansion of an ejection bubble 48 is prevented from reversely flowing into the supply flow channel, the ejection speed of an ink droplet 50 is increased, and also the flight direction of the ink droplet 50 is stabilized.
However, in the inkjet printer described in Japanese Patent Application Publication No. 2004-42395, since the second bubble generation chamber 26B abutting against the nozzle plate 40 is provided as shown in FIGS. 11A to 11E, then a liquid pool 70 occurs at the corner sections of the second bubble generation chamber 26B when the expansion of the ejection bubble 48 progresses to a state (shown in FIG. 11B) immediately before the ejection bubble 48 is incorporated into the atmosphere. Hence, when the ejection bubble 48 is discharged and is incorporated into the atmosphere (FIGS. 11D and 11E), then the liquid pool 70 is also discharged in the form of a droplet, resulting in the generation of a satellite droplet 52. The frequency of occurrence of dot disturbance may be thereby increased, and consequently, it is difficult to achieve the desired dot shape.